Light Reflecting Mirror Structure for Thermal Drift Suppression
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Solution Overview
Problem
The challenge is to prevent the deviation of reflected light from a desired direction due to thermal changes in the environment, which can cause deformation and strain stress in the light reflecting device, affecting the accuracy of sensors and lighting devices.
Innovation Solution
The light reflecting device is designed with specific material selections and structural modifications, such as varying thermal expansion coefficients and increased distances from the mirror face, to minimize strain stress and maintain the desired light direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light reflecting device uses a conventional structure with uniform thickness, then the device is simple to manufacture, but thermal changes cause strain stress concentration at bonding positions leading to mirror face deformation and light direction deviation
Solution Approach 1:
The patent applies local quality by creating a thick portion at a specific position of the light reflecting member, where the thickness in the direction intersecting the mirror face is increased compared to other portions. This localized structural modification allows strain stress to be distributed away from the mirror face during thermal changes, preventing deformation while maintaining overall structural simplicity.
2Reliability
If the light reflecting device uses a conventional bonding structure, then the device structure is simple, but strain stress concentrates at the bonding position between the arm member and light reflecting member causing mirror face strain
Solution Approach 1:
The patent creates a localized thick portion in the light reflecting member at the bonding position with the arm member. This thick portion is positioned such that when the arm member bonds to the light reflecting member, the bonding interface is located away from the mirror face, preventing strain stress from reaching the mirror face during thermal expansion or contraction.
3Reliability
If the light reflecting device uses a structure without thermal expansion consideration, then the device design is simple, but thermal changes cause deformation of the light reflecting member and arm member leading to light direction deviation
Solution Approach 1:
The patent addresses thermal expansion by designing a thick portion in the light reflecting member at a position where thermal deformation would otherwise concentrate strain at the bonding interface. This structural feature compensates for thermal expansion effects by creating a stress distribution pattern that protects the mirror face from strain during temperature changes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively suppresses the deviation of reflected light direction due to thermal changes, enhancing the accuracy of both sensor detection and lighting pattern formation.
Implementation Method 1
A thermal change of the environment in which the light reflecting device is disposed may cause deformation of each of the light reflecting member and the arm member. Strain stress that may occur as a result of the deformation is likely to concentrate at a position where the arm member is bonded to the light reflecting member. However, by forming the thick portion so that the distance from the mirror face is increased at such a position, the strain stress can be made difficult to reach the mirror face.
Data Source
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AI summary
A light reflecting member (11) has a mirror face (111) adapted to reflect incident light (IL). A first arm member (121) and a second arm member (122) are bonded to the light reflecting member (11). A first actuator (131) and a second actuator (132) are configured to cause the first arm member (121) and the second arm member (122) respectively to displace in a direction intersecting the mirror face (111) to change an angle of the mirror face (111) relative to the incident light (IL). A thermal expansion coefficient of a material forming the light reflecting member (11) is smaller than a thermal expansion coefficient of a material forming each of the first arm member (121) and the second arm member (122).